A Commando That Got Away

Status
Not open for further replies.
Joined
Jun 17, 2009
Messages
642
Bought a 1972 Combat new that year. Had the ports shaped and polished, and got a Blair two into one into two exhaust.
I was 21, damn it was fast. Rode it from Minnesota that summer to San Fransisco and back home. Put a handlebar winshield
on it and hung the sleeping bag on a short sissy bar.
Coming back to Minnesota while going over Independence Pass in the Rockies, the motor overheated and the rear wheel locked while
going down the pass at 75mph, sheer terror, fishtailing with a raft of cars behind me. Tried to pull in the clutch and it straightened up
and damn near threw me off. Got it stopped on the side of the Interstate and sat there shaking for an hour.
It started up and I made it slowly back home.
I had to sell the bike in the fall to raise money for the next year of college. I regret ever selling it, wish I could have somehow kept it.
Very fond memories, especially of its brutal acceleration!
 
The Good, the Bad, and the Ugly.

Such is life with (and without) Commandos...
 
I took my j'72 750 combat to the mountain station above Palm Springs, Ca in 1973 - age 20. The parking lot is at the top of a very steep hill, so I decided to roll down the hill and bump start the engine. Got is rolling to 40mph and dropped the clutch in 4th gear. It skidded to a stop. That's compression!
 
You know, that's something I've always wondered about. The (non-Combat) Commandos have a relatively low compression ratio. Why, then, are they so bloody hard to kick over? When you first hit compression, it's like the kickstarter has made metal to metal contact with an immovable object! And of course, the engine braking on the overrun is impressive. No wonder they didn't put real brakes on the things...!
 
Kickstarting force is a product of the kickstart mechanism and it's gearing ratio relative to the crankshaft.
 
On the kickstart gearing ratio, a single 450 ducati feels as though it has the compression ratio of a diesel, a fat person can stand for some time on the kick start before it falls over TDC. In fact the compression is only about 9:1
These things will only clutch start in 1st gear, any other gear will just lock the rear wheel.
(a good anti theft device)
 
BrianK said:
Thanks Grandpaul. So is the Norton K/S basically undergeared/underleveraged?

I've got a 72 Combat.
Looking to get a little better leverage the 850 kicker appears a litle longer.
I get one on e-bay with great chrome, but I didn't think to ask about splines. Lousy. :( No point in messing up the tranny pounding it on.
Still looking but thinking it may help with the longer lever arm.

Bob
 
A couple of things are going on here. The transmission kicker ratio was designed for a much older and lower compression bike, and Nortons have a short lever. Of course you can fix this with a belt drive or a longer lever. The mark 3 lever I had gives more clearance but is not effectively longer. I added a couple of inches to it and it makes a big difference.
 
Status
Not open for further replies.
Back
Top